JP5071044B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging device having an optical finder function and an electronic finder function.

  In a single-lens reflex type (hereinafter also abbreviated as “single-lens reflex type”) digital camera, the subject is generally confirmed with an optical viewfinder, but it has an electronic viewfinder function that displays the subject on a monitor in a moving image mode. Has been proposed (Patent Document 1).

  And in patent document 1, when performing composition determination operation using an electronic finder (in electronic finder mode), AF control of a contrast detection system is performed in a mirror-up state, and using an optical finder (in optical finder mode) In the case of performing the composition determination operation, a technique for performing phase difference detection type AF control in a mirror-down state has been proposed.

  Here, in the phase difference detection type AF control performed in the mirror-down state, a phase difference AF module having a photometric sensor such as a line sensor is usually used. However, in principle, the phase difference AF module has a large number of AF areas. I can't take it. On the other hand, in contrast detection AF control, a large number of AF areas can be defined in the imaging surface.

JP 2006-251065 A

  For this reason, in the technique described in Patent Document 1, after determining the AF area (also referred to as “AF target area”) to be focused in the composition determination operation in the electronic finder mode, the finder mode is changed to the optical finder mode. There may be no AF area used for phase difference detection AF control at the position of the AF target area. In such a case, the user performs the angle of view adjustment again, and the operation becomes complicated.

  Therefore, an object of the present invention is to provide an imaging apparatus capable of avoiding re-focusing of an angle of view when phase difference detection AF control is performed after execution of the electronic finder mode.

  A first aspect of the present invention is an imaging device, which receives subject light by an imaging element that receives subject light and generates an image signal related to the subject image, a display unit, and a distance measuring sensor, Based on a phase difference detection unit that generates a phase difference detection signal, first focusing means that performs first focusing control based on the phase difference detection signal, and image signals that are sequentially generated by the imaging device, Display control means for displaying a preview image before actual photographing on the display section, and the display control means displays the first area where phase difference detection is performed by the distance measuring sensor combined with the preview image. It is characterized by that.

  According to a second aspect of the present invention, there is provided an imaging device that receives subject light incident from a photographing optical system and generates an image signal related to a subject image, a display unit, and the subject light. And a first mirror which is set at a predetermined position in the photographing region by receiving the subject light whose optical path has been changed by the mirror with a distance measuring sensor. A phase difference detection unit that generates a phase difference detection signal in the area; a first focusing unit that performs first focusing control based on the phase difference detection signal; and a mirror control unit that retracts the mirror unit from the optical path; Display control means for performing a preview display before actual photographing on the display unit based on image signals sequentially generated by the imaging element in a state where the mirror unit is retracted from the optical path, and the display control Stage, when the preview display, and wherein the displaying the first area in which the phase difference detection is performed by the distance measuring sensor on the display unit.

  According to the present invention, since the first area in which the phase difference detection is performed by the distance measurement sensor of the phase difference detection unit is combined with the preview image and displayed, it is based on the phase difference detection signal generated by the distance measurement sensor. When performing the first focusing control, it is possible to avoid the angle of view alignment again.

<1. First Embodiment>
<External Configuration of Imaging Device 1A>
1 and 2 are diagrams showing an external configuration of an imaging apparatus 1A according to the first embodiment of the present invention. Here, FIGS. 1 and 2 show a front view and a rear view, respectively.

  The imaging apparatus 1 </ b> A is configured as, for example, a single-lens reflex digital still camera, and includes a camera body 10 and an interchangeable lens 2 as a photographic lens that is detachable from the camera body 10.

  Specifically, as shown in FIG. 1, on the front side of the camera body 10, a mount portion 301 on which the interchangeable lens 2 is mounted at the front center and a lens exchange disposed on the right side of the mount portion 301. A button 302, a grip portion 303 for enabling gripping, a mode setting dial 305 disposed at the upper left portion of the front surface, a control value setting dial 306 disposed at the upper right portion of the front surface, and an upper surface of the grip portion 303. A shutter button 307 is provided.

  The interchangeable lens 2 functions as a lens window that captures light from the subject (subject light), and also functions as a photographing optical system for guiding the subject light to the image sensor 101 disposed inside the camera body 10.

  More specifically, the interchangeable lens 2 includes a lens group 21 composed of a plurality of lenses arranged in series along the optical axis LT (see FIG. 5). The lens group 21 includes a focus lens 211 (FIG. 5) for adjusting the focus and a zoom lens 212 (FIG. 5) for zooming, and each includes an optical axis LT (FIG. 3). Focusing or scaling is performed by being driven in the direction of (see). Further, the interchangeable lens 2 is provided with an operation ring that can rotate along the outer peripheral surface of the lens barrel at a suitable position on the outer periphery of the lens barrel. The zoom lens 212 can be operated by manual operation or automatic operation. It moves in the optical axis direction according to the rotation direction and rotation amount of the operation ring, and is set to a zoom magnification (imaging magnification) according to the position of the movement destination.

  The mount 301 is provided with a connector Ec (see FIG. 5) for electrical connection with the mounted interchangeable lens 2 and a coupler 75 (FIG. 5) for mechanical connection.

  The lens exchange button 302 is a button that is pressed when the interchangeable lens 2 attached to the mount unit 301 is removed.

  The grip portion 303 is a portion where the photographer (user) grips the imaging device 1A at the time of photographing, and is provided with surface irregularities that match the finger shape in order to improve fitting properties. Note that a battery storage chamber and a card storage chamber (not shown) are provided inside the grip portion 303. A battery 69B (see FIG. 5) is stored in the battery storage chamber as a power source of the image pickup apparatus 1A, and a memory card 67 (FIG. 5) for recording image data of a photographed image is detachable in the card storage chamber. It is designed to be stored. The grip unit 303 may be provided with a grip sensor for detecting whether or not the user has gripped the grip unit 303.

  The mode setting dial 305 and the control value setting dial 306 are made of a substantially disk-shaped member that can rotate in a plane substantially parallel to the upper surface of the camera body 10. The mode setting dial 305 is used for various modes (such as various shooting modes (portrait shooting mode, landscape shooting mode, full-auto shooting mode, etc.), a playback mode for playing back a shot image, and an external device. This is for selecting a communication mode for performing data communication. On the other hand, the control value setting dial 306 is for setting control values for various functions installed in the imaging apparatus 1A.

  The shutter button 307 is a push switch that can detect a “half-pressed state” that is pressed halfway and a “full-pressed state” that is further pressed. When the shutter button 307 is half-pressed (S1) in the shooting mode, a preparatory operation (preparation operation for setting an exposure control value, focus detection, etc.) for photographing a still image of the subject is executed, and the shutter button 307 is fully pressed. When pressed (S2), a shooting operation (a series of operations for exposing the image sensor 101 (see FIG. 3), performing predetermined image processing on the image signal obtained by the exposure, and recording the image signal on a memory card or the like) is performed. Executed.

  As shown in FIG. 2, an LCD (Liquid Crystal Display) 311 that functions as a display unit, a finder window 316 disposed above the LCD 311, and a finder window 316 are provided on the back side of the camera body 10. The surrounding eyecup 321, the main switch 317 disposed on the left side of the finder window 316, the exposure correction button 323 and the AE lock button 324 disposed on the right side of the finder window 316, and the finder window 316 A flash unit 318 and a connection terminal unit 319 disposed above are provided. On the back side of the camera body 10, a setting button group 312 disposed on the left side of the LCD 311, a direction selection key 314 disposed on the right side of the LCD 311, and a push disposed on the center of the direction selection key 314. A button 315 and a display changeover switch 85 arranged at the lower right of the direction selection key 314 are provided.

  The LCD 311 includes a color liquid crystal panel capable of displaying an image, and displays an image captured by the image sensor 101 (see FIG. 3) or reproduces and displays a recorded image, and is mounted on the image capturing apparatus 1A. Function or mode setting screen. Note that an organic EL display device or a plasma display device may be used instead of the LCD 311.

  The viewfinder window (eyepiece window) 316 forms an optical viewfinder (OVF), and light (subject light) that forms a subject image that has passed through the interchangeable lens 2 is guided to the viewfinder window 316. The user can view the subject image actually captured by the image sensor 101 by looking through the finder window 316.

  The main switch 317 is a two-contact slide switch that slides to the left and right. When the switch is set to the left, the power of the image pickup apparatus 1A is turned on.

  The flash unit 318 is configured as a pop-up built-in flash. On the other hand, when attaching an external flash or the like to the camera body 10, the connection is made using the connection terminal portion 319.

  The eye cup 321 is a “U” -shaped light shielding member that suppresses intrusion of external light into the finder window 316.

  The exposure correction button 323 is a button for manually adjusting the exposure value (aperture value and shutter speed), and the AE lock button 324 is a button for fixing the exposure.

  The setting button group 312 is a button for performing operations on various functions installed in the imaging apparatus 1A. The setting button group 312 includes, for example, a menu button for displaying a menu screen on the LCD 311 and a menu switching button for switching the contents of the menu screen.

  The direction selection key 314 has an annular member having a plurality of pressing portions (triangle marks in the drawing) arranged at regular intervals in the circumferential direction, and is not shown provided corresponding to each pressing portion. The pressing operation of the pressing portion is detected by the contact (switch). The push button 315 is disposed at the center of the direction selection key 314. The direction selection key 314 and the push button 315 are used to change the shooting magnification (movement of the zoom lens 212 (see FIG. 5) in the wide direction or the tele direction), frame advance of a recorded image to be reproduced on the LCD 311 and the like, and shooting conditions (aperture). Value, shutter speed, presence / absence of flash emission, etc.).

  The display changeover switch 85 is composed of two slide switches. When the contact point is set at the upper “optical” position, the optical finder mode (also referred to as “OVF mode”) is selected, and the subject image is displayed in the optical finder field of view. The Accordingly, the user can perform a composition determination operation (framing) by visually recognizing the subject image displayed in the optical viewfinder field through the viewfinder window 316.

  On the other hand, when the contact of the display changeover switch 85 is set to the lower “monitor” position, the electronic finder mode (also referred to as “EVF mode” or “live view mode”) is selected, and the live view image related to the subject image is displayed on the LCD 311 as a moving image. Displayed in a specific manner. Thereby, the user can perform framing by visually recognizing the live view image displayed on the LCD 311.

  As described above, the user can switch the finder mode by operating the display changeover switch 85, and the imaging apparatus 1A determines the composition of the subject using the electronic finder or the optical finder on which the live view display is performed. Is possible.

<Internal Configuration of Imaging Device 1A>
Next, the internal configuration of the imaging apparatus 1A will be described. 3 and 4 are longitudinal sectional views of the imaging apparatus 1A. As shown in FIG. 3, the camera body 10 includes an image sensor 101, a finder unit 102 (finder optical system), a mirror unit 103, a phase difference AF module (also simply referred to as “AF module”) 107, and the like. ing.

  The imaging element 101 is disposed perpendicular to the optical axis LT on the optical axis LT of the lens group 21 provided in the interchangeable lens 2 when the interchangeable lens 2 is attached to the camera body 10. As the image sensor 101, for example, a CMOS color area sensor (CMOS type image sensor) in which a plurality of pixels configured with photodiodes are two-dimensionally arranged in a matrix is used. The image sensor 101 generates analog electrical signals (image signals) of R (red), G (green), and B (blue) color components related to the subject image formed through the interchangeable lens 2, and R, G , B are output as image signals of respective colors.

  In addition, the imaging element 101 has a light receiving element for detecting a phase difference on the imaging surface. Details will be described later.

  On the optical axis LT, a mirror unit 103 is disposed at a position where subject light is reflected toward the viewfinder unit 102. The subject light that has passed through the interchangeable lens 2 is reflected upward by a mirror unit 103 (a main mirror 1031 described later), and part of the subject light is transmitted through the mirror unit 103.

  The finder unit 102 includes a pentaprism 105, an eyepiece lens 106, and a finder window 316. The pentaprism 105 has a pentagonal cross section, and is a prism for changing the top and right sides of the optical image into an upright image by reflection inside the subject image incident from the lower surface thereof. The eyepiece 106 guides the subject image that has been made an erect image by the pentaprism 105 to the outside of the finder window 316. With such a configuration, the finder unit 102 functions as an optical finder for confirming the object scene at the time of shooting standby before main shooting.

  The mirror unit 103 includes a main mirror 1031 and a sub mirror 1032, and is provided on the back side of the main mirror 1031 so that the sub mirror 1032 can be tilted toward the back of the main mirror 1031. Part of the subject light transmitted through the main mirror 1031 is reflected by the sub mirror 1032, and the reflected subject light enters the AF module 107.

  The mirror unit 103 is configured as a so-called quick return mirror. For example, during exposure (main shooting) (see FIG. 4), the mirror unit 103 jumps upward with the rotating shaft 1033 as a fulcrum, and from the optical path of the subject light. It is in a retracted state (mirror up state). At this time, the sub mirror 1032 is folded so as to be substantially parallel to the main mirror 1031 when the mirror unit 103 stops at a position below the pentaprism 105. As a result, the subject light from the interchangeable lens 2 reaches the image sensor 101 without being blocked by the mirror 103, and the image sensor 101 is exposed. When the image pickup operation by the image pickup device 101 is completed, the mirror unit 103 returns to the original position (position shown in FIG. 3) and enters the mirror down state.

  In addition, by setting the mirror unit 103 in the mirror-up state before the main shooting (shooting for image recording), the imaging apparatus 1 </ b> A has a moving image mode based on the image signals sequentially generated by the imaging device 101. Live view (preview) display in which the subject is displayed on the LCD 311 is possible.

  The AF module 107 is configured as a so-called AF sensor including a distance measuring element (also referred to as a “range sensor”) for detecting focus information of a subject. The AF module 107 is disposed at the bottom of the mirror unit 103 and has a phase difference detection function for generating a phase difference detection signal corresponding to the degree of focus of the subject image. That is, when the user checks the subject through the viewfinder window 316 during shooting standby, the subject light is guided to the AF module 107 with the main mirror 1031 and the sub mirror 1032 down as shown in FIG. A phase difference detection signal is output from the module 107.

  A shutter unit 40 is disposed in front of the image sensor 101 in the optical axis direction. The shutter unit 40 includes a curtain body that moves in the vertical direction, and is configured as a mechanical focal plane shutter that performs an optical path opening operation and an optical path blocking operation of subject light guided to the image sensor 101 along the optical axis LT. The shutter unit 40 can be omitted when the image sensor 101 is an image sensor capable of complete electronic shutter.

<Electrical Configuration of Imaging Device 1A>
FIG. 5 is a block diagram illustrating an electrical configuration of the imaging apparatus 1A. Here, the same members and the like as those in FIGS. 1 to 4 are denoted by the same reference numerals. For convenience of explanation, the electrical configuration of the interchangeable lens 2 will be described first.

  The interchangeable lens 2 includes a lens drive mechanism 24, a lens position detection unit 25, a lens control unit 26, and a diaphragm drive mechanism 27 in addition to the lens group 21 constituting the above-described photographing optical system.

  In the lens group 21, a focus lens 211 and a zoom lens 212, and a diaphragm 23 for adjusting the amount of light incident on the image sensor 101 are held in the direction of the optical axis LT (FIG. 3) in the lens barrel. The subject light captured by the lens group 21 is imaged on the image sensor 101. In automatic focusing (AF) control, the focus lens 211 is driven in the direction of the optical axis LT by the AF actuator 71M in the interchangeable lens 2 to perform focus adjustment.

  The focus drive control unit 71A generates a drive control signal necessary for moving the focus lens 211 to the in-focus position based on the AF control signal given from the overall control unit 62 via the lens control unit 26, and the drive The AF actuator 71M is controlled using the control signal. The AF actuator 71M is composed of a stepping motor or the like, and applies a lens driving force to the lens driving mechanism 24.

  The lens driving mechanism 24 includes, for example, a helicoid and a gear (not shown) that rotates the helicoid, and receives the driving force from the AF actuator 71M to drive the focus lens 211 and the like in a direction parallel to the optical axis LT. It is. The moving direction and moving amount of the focus lens 211 are in accordance with the rotating direction and the rotating speed of the AF actuator 71M, respectively.

  The lens position detection unit 25 moves integrally with the lens while being in sliding contact with the encode plate in which a plurality of code patterns are formed at a predetermined pitch in the optical axis LT direction within the movement range of the lens group 21. An encoder brush, and detects the amount of movement of the lens group 21 during focus adjustment. The lens position detected by the lens position detection unit 24 is output as the number of pulses, for example.

  The lens control unit 26 is composed of, for example, a microcomputer having a built-in memory such as a ROM that stores a control program or a flash memory that stores data relating to status information.

  The lens control unit 26 has a communication function for communicating with the overall control unit 62 of the camera body 10 via the connector Ec. Thereby, for example, the state information data such as the focal length, the aperture value, the focusing distance or the peripheral light amount state of the lens group 21 and the position information of the focus lens 211 detected by the lens position detection unit 25 are transmitted to the overall control unit 62. In addition, the driving amount data of the focus lens 211 can be received from the overall control unit 62, for example.

  The aperture drive mechanism 27 receives the driving force from the aperture drive actuator 76M via the coupler 75 and changes the aperture diameter of the aperture 23.

  Next, the electrical configuration of the camera body 10 will be described. The camera body 10 includes an AFE (analog front end) 5, an image processing unit 61, an image memory 614, an overall control unit 62, a flash circuit 63, an operation unit 64, and a VRAM 65 in addition to the above-described imaging device 101 and shutter unit 40. Card I / F 66, memory card 67, communication I / F 68, power supply circuit 69, battery 69B, mirror drive control unit 72A, shutter drive control unit 73A, and aperture drive control unit 76A.

  The image sensor 101 is composed of a CMOS color area sensor as described above, and the timing control circuit 51 described below starts (and ends) the exposure operation of the image sensor 101, selects the output of each pixel included in the image sensor 101, In addition, an imaging operation such as readout of pixel signals is controlled.

  The AFE 5 gives a timing pulse for causing the image sensor 101 to perform a predetermined operation, performs predetermined signal processing on the image signal output from the image sensor 101, converts the image signal to a digital signal, and outputs the digital signal to the image processing unit 61. It has a function to do. The AFE 5 includes a timing control circuit 51, a signal processing unit 52, an A / D conversion unit 53, and the like.

  The timing control circuit 51 generates a predetermined timing pulse (a pulse for generating a vertical scanning pulse φVn, a horizontal scanning pulse φVm, a reset signal φVr, and the like) based on the reference clock output from the overall control unit 62, and the imaging device 101. And the imaging operation of the image sensor 101 is controlled. In addition, the operation of the signal processing unit 52 and the A / D conversion unit 53 is controlled by outputting predetermined timing pulses to the signal processing unit 52 and the A / D conversion unit 53, respectively.

  The signal processing unit 52 performs predetermined analog signal processing on the analog image signal output from the image sensor 101. The signal processing unit 52 includes a CDS (correlated double sampling) circuit, an AGC (auto gain control) circuit, a clamp circuit, and the like. The A / D conversion unit 53 converts the analog R, G, B image signals output from the signal processing unit 52 into a plurality of bits (for example, 12 bits) based on the timing pulse output from the timing control circuit 51. Is converted into a digital image signal.

  The image processing unit 61 performs predetermined signal processing on the image data output from the AFE 5 to create an image file, and includes a black level correction circuit 611, a white balance control circuit 612, a gamma correction circuit 613, and the like. Has been. The image data captured by the image processing unit 61 is temporarily written in the image memory 614 in synchronization with the reading of the image sensor 101. Thereafter, the image data written in the image memory 614 is accessed to access the image processing unit. Processing is performed in each of the 61 blocks.

  The black level correction circuit 611 corrects the black level of each of the R, G, and B digital image signals A / D converted by the A / D conversion unit 53 to a reference black level.

  The white balance control circuit 612 performs level conversion (white balance (WB) adjustment) of digital signals of R (red), G (green), and B (blue) color components based on the white reference corresponding to the light source. . Specifically, the white balance control circuit 612 identifies a portion that is originally estimated to be white in the photographic subject from the luminance or saturation data based on the WB adjustment data provided from the overall control unit 62, and the portion. The R, G, and B color component averages, the G / R ratio, and the G / B ratio are obtained, and the levels are corrected as R and B correction gains.

  The gamma correction circuit 613 corrects the gradation characteristics of the image data subjected to WB adjustment. Specifically, the gamma correction circuit 613 performs non-linear conversion of the image data level for each color component and offset adjustment using a preset gamma correction table.

  The image memory 614 temporarily stores the image data output from the image processing unit 61 in the shooting mode and is used as a work area for performing predetermined processing on the image data by the overall control unit 62. It is. In the playback mode, the image data read from the memory card 67 is temporarily stored.

  The overall control unit 62 is configured as a microcomputer and mainly includes a CPU, a memory, a ROM, and the like. The overall control unit 62 reads out a program stored in the ROM and executes the program by the CPU, thereby realizing various functions of the imaging apparatus 1A.

  The overall control unit 62 functionally realizes the display control unit 62A, the phase difference AF control unit 62B, and the contrast AF control unit 62C by executing the above-described program.

  The display control unit 62A controls the display contents on the LCD 311. For example, the display control unit 62A causes the LCD 311 to sequentially display each of a plurality of images continuously acquired by the image sensor 101 as a live view image.

  Further, the display control unit 62A synthesizes and superimposes an area (also referred to as “AF area”, “distance area”, or “focus area”) Ef for acquiring focus information used for the AF operation on the live view image. . Details will be described later.

  The phase difference AF control unit 62B detects the in-focus position by the phase difference detection method and executes an automatic focusing operation. Specifically, the phase difference AF control unit 62 </ b> B is configured to detect the photographing lens at the time of focusing (from the phase difference detection signal acquired by the AF module 107 or the output signal from the phase difference AF calculation circuit 77 (described later)). Specifically, a focus lens position specifying operation for specifying the position (focus lens position) of the focus lens is performed.

  The contrast AF control unit 62C detects an in-focus position by a contrast detection method and executes an automatic focusing operation (also referred to as “contrast AF operation”). Specifically, the contrast AF control unit 62C optimizes the evaluation value and an evaluation value calculation operation for obtaining an evaluation value corresponding to the contrast of the subject image for a plurality of captured images acquired at different lens positions ( For example, a focusing lens position specifying operation for specifying a lens position to be minimized as a focusing lens position is executed.

  The flash circuit 63 controls the light emission amount of the external flash connected to the flash unit 318 or the connection terminal unit 319 to the light emission amount set by the overall control unit 62 in the flash photographing mode.

  The operation unit 64 includes the mode setting dial 305, the control value setting dial 306, the shutter button 307, the setting button group 312, the direction selection key 314, the push button 315, the main switch 317, and the like. 62 for input.

  The VRAM 65 has an image signal storage capacity corresponding to the number of pixels of the LCD 311 and is a buffer memory between the overall control unit 62 and the LCD 311. The card I / F 66 is an interface for enabling transmission / reception of signals between the memory card 67 and the overall control unit 62. The memory card 67 is a recording medium that stores image data generated by the overall control unit 62. The communication I / F 68 is an interface for enabling transmission of image data and the like to a personal computer or other external device.

  The power supply circuit 69 includes a constant voltage circuit, for example, and generates a voltage for driving the entire imaging apparatus 1A, such as a control unit such as the overall control unit 62, the imaging element 101, and other various driving units. Note that energization control to the image sensor 101 is performed by a control signal supplied from the overall control unit 62 to the power supply circuit 69. The battery 69B includes a primary battery such as an alkaline battery or a secondary battery such as a nickel metal hydride battery, and is a power source that supplies power to the entire imaging apparatus 1A.

  The mirror drive control unit 72A generates a drive signal for driving the mirror drive actuator 72M in accordance with the switching of the finder mode or the timing of the photographing operation. The mirror drive actuator 72M is an actuator that rotates the mirror unit 103 (quick return mirror) to a horizontal posture or an inclined posture.

  The shutter drive control unit 73A generates a drive control signal for the shutter drive actuator 73M based on a control signal given from the overall control unit 62. The shutter drive actuator 73M is an actuator that opens and closes the shutter unit 40.

  The aperture drive control unit 76A generates a drive control signal for the aperture drive actuator 76M based on the control signal given from the overall control unit 62. The aperture driving actuator 76M applies a driving force to the aperture driving mechanism 27 via the coupler 75.

  The camera body 10 also includes a phase difference AF calculation circuit 77 that performs calculations necessary for autofocus (AF) control based on the black level corrected image data output from the black level correction circuit 611.

  Hereinafter, the phase difference AF operation using the output signal from the phase difference AF calculation circuit 77 will be described in detail, and the AF operation that can be executed by the imaging apparatus 1A will be described.

<AF Operation of Imaging Device 1A>
The imaging apparatus 1A has a configuration capable of performing phase difference AF by causing the imaging element 101 to receive transmitted light that has been transmitted (passed) through different portions of the exit pupil of the photographing lens. In the following, first, the configuration of the image sensor 101 and the principle of phase difference AF using the image sensor 101 will be described. 6 and 7 are diagrams for explaining the configuration of the image sensor 101.

  The imaging element 101 has a configuration capable of performing focus detection by a phase difference detection method for each AF area Ef defined in a matrix on the imaging surface 101f (FIG. 6).

  Each AF area Ef has a normal pixel composed of an R pixel 111, a G pixel 112, and a B pixel 113 in which R (red), G (green), and B (blue) color filters are arranged on a photodiode. (Hereinafter also referred to as “normal pixel”) 110 and a pixel (hereinafter also referred to as “AF pixel”) 11 f for performing phase difference AF having light shielding plates 12 a and 12 b (parallel oblique line portions) described later. Is provided (FIG. 7).

  In the AF area Ef, Gr lines L1 in which G pixels 112 and R pixels 111 are alternately arranged in the horizontal direction as horizontal lines of normal pixels, and B pixels 113 and G pixels 112 are alternately arranged in the horizontal direction. An arranged Gb line L2 is formed. A Bayer arrangement is configured by alternately arranging the Gr lines L1 and Gb lines L2 in the vertical direction.

  In the AF area Ef, for example, AF lines Lf are formed in which AF pixels 11f are arranged in the horizontal direction for every six horizontal lines of the normal pixels. In the AF area Ef, for example, about 20 AF lines Lf are provided.

  Next, the principle of phase difference AF using the AF line Lf will be described in detail.

  FIG. 8 is a diagram for explaining the principle of phase difference AF using the AF line Lf.

  In the AF line Lf, a light shielding plate 12a whose mirror surface is the position of the opening OP for separating the light beam Ta from the right portion Qa of the exit pupil and the light beam Tb from the left portion Qb of the interchangeable lens 2 A pair of pixels 11a and 11b having 12b are arranged in the horizontal direction. More specifically, a pixel (hereinafter also referred to as a “first AF pixel”) 11a having a light shielding plate 12a in which a slit-like opening OP is biased to the right with respect to the photoelectric conversion portion (photodiode) PD immediately below, and a slit Pixels (hereinafter also referred to as “second AF pixels”) 11 b having light-shielding plates 12 b in which the apertures OP are biased to the left with respect to the photoelectric conversion portions PD directly below are alternately arranged on the AF lines Lf ( Fig. 7).

  As a result, the light beam Ta from the right part Qa of the exit pupil passes through the microlens ML and the opening OP of the light shielding plate 12a and is received by the photoelectric conversion unit PD of the first AF pixel 11a, and the light beam from the left part Qb of the exit pupil. Tb passes through the microlens ML and the opening OP of the light shielding plate 12b and is received by the photoelectric conversion unit PD of the second AF pixel 11b. In other words, the pair of pixels 11a and 11b receive the light fluxes Ta and Tb of the subject that have passed through the right part and the left part (a pair of partial areas) Qa and Qb in the exit pupil of the interchangeable lens 2, respectively.

  Hereinafter, the pixel output of the first AF pixel 11a is referred to as “a series pixel output”, and the pixel output of the second AF pixel 11b is referred to as “b series pixel output”. For example, one AF line Lf The relationship between the a-series pixel output and the b-series pixel output obtained from the pixel array of the AF pixels 11f arranged in FIG. 9 will be described with reference to FIGS. FIG. 9 is a diagram illustrating the relationship between the light beam incident from the exit pupil of the photographing lens and the AF pixel 11 f of the image sensor 101. FIG. 10 is a diagram illustrating the pixel output of the AF line Lf. FIG. 11 is a diagram illustrating the shift amount Sf and the defocus amount Df of the pixel output.

  In the AF line Lf, for example, as shown in FIG. 9, the light beams Ta and Tb from both sides of the exit pupil are received by the first AF pixel 11a and the second AF pixel 11b. Here, the a-sequence pixel output in the AF line Lf including the a-sequence pixels a1 to a3 arranged as shown in FIG. 9 is represented as a graph Ga (shown by a solid line) in FIG. On the other hand, the b-sequence pixel output in the AF line Lf including the b-sequence pixels b1 to b3 arranged as shown in FIG. 9 is represented as a graph Gb (shown by a broken line) in FIG.

  Comparing the graph Ga and the graph Gb shown in FIG. 10, the phase difference between the a-sequence pixel output and the b-sequence pixel output is generated by a shift amount (shift amount) Sf in the AF line Lf direction. I understand.

  On the other hand, the relationship between the shift amount Sf and the amount of defocusing of the focal plane with respect to the imaging surface of the image sensor 101 (defocus amount) Df is represented by a linear function graph Gc shown in FIG. Is done. The inclination of the graph Gc can be acquired in advance by a factory test or the like.

  Therefore, after obtaining the shift amount Sf by the phase difference AF calculation circuit 77 based on the output of the AF line Lf of the image sensor 101, the phase difference AF control unit 62B calculates the defocus amount Df based on the graph Gc in FIG. Then, by applying a driving amount corresponding to the calculated defocus amount Df to the focus lens 211, the phase difference AF that moves the focus lens 211 to the in-focus position becomes possible.

  As described above, in the image pickup apparatus 1A, the phase difference detection type automatic focusing operation using the output signal from the light receiving element incorporated in the light receiving surface of the image pickup element 101 (also referred to as “phase difference AF operation by the image pickup element 101”). ) Can be performed.

  The image pickup apparatus 1A has a function of performing a phase difference AF operation and a contrast AF operation by the AF module 107 in addition to the phase difference AF operation by the image pickup element 101. However, each of these AF operations can be executed. Whether or not it exists depends on the selected finder mode.

  Specifically, in the OVF mode, the mirror is down (FIG. 3) and a part of the subject light is guided to the AF module 107. Therefore, as the AF operation, an output signal from the light receiving element in the AF module 107 is used. The AF operation of the used phase difference detection method (also referred to as “phase difference AF operation by the AF module 107”) can be executed.

  On the other hand, in the EVF mode, the mirror-up state (FIG. 4) is entered, and the subject light is guided to the image sensor 101. Therefore, as the AF operation, the phase difference AF operation and / or the contrast AF operation by the image sensor 101 can be executed. Become. As an AF operation in the EVF mode, which AF operation is to be executed among the AF operations using the image sensor 101 (phase difference AF operation and contrast AF operation by the image sensor 101) is determined on the menu screen. It can be determined by operation.

<Basic Operation of Imaging Device 1A>
Next, the basic operation of the imaging apparatus 1A will be described. 12 and 13 are flowcharts of the photographing operation of the imaging apparatus 1A. 14 and 15 are diagrams showing display examples of the AF area Ef on the LCD 311. FIG.

  When the shooting mode is selected by a dial operation using the mode setting dial 305 of the imaging apparatus 1A, the shooting operation shown in FIGS. 12 and 13 is executed.

  Specifically, as shown in FIG. 12, first, in step SP1, it is determined whether or not the EVF mode is selected by operating the display changeover switch 85. If it is determined that the EVF mode is not selected, the process proceeds to step SP21 (FIG. 13), and the composition determining operation in the OVF mode can be executed. Each process after step SP21 will be described later.

  On the other hand, if it is determined that the EVF mode is selected, the process proceeds to step SP2, and the composition determination operation in the EVF mode can be executed.

  Specifically, in step SP2, the mirror unit 103 is driven, and the mirror unit 103 is retracted from the optical path of the subject light passing through the interchangeable lens 2.

  In step SP3, the shutter unit 40 is opened, and in step SP4, the image sensor 101 is activated, and an image signal can be generated by exposure.

  In step SP5, power supply to the LCD 311 is started, and display of a live view image on the LCD 311 is started by the display control unit 62A based on image signals sequentially generated by the image sensor 101.

  Further, the AF area Ef is displayed on the LCD 311 by the display control unit 62A. Specifically, as shown in FIG. 14, the LCD 311 has an AF area (also referred to as “image AF area”) FR <b> 1 (a rectangle drawn by a solid line in FIG. 14) used for an AF operation using the image sensor 101. Area) is displayed in combination with the live view image and is used for the phase difference AF operation by the AF module 107 (also referred to as “module AF area”) FR2 (rectangular area drawn by a broken line in FIG. 14). Is also displayed in the live view image.

  Thus, by displaying the module AF area FR2 used for the phase difference AF operation by the AF module 107 on the LCD 311 in the EVF mode, the user can use the module AF area used in the OVF mode even in the EVF mode. FR2 can be recognized. According to this, even when the user plans to change the mode from the EVF mode to the OVF mode after the end of the framing in the EVF mode, the user should adjust the subject to the module AF area FR2 in advance in the EVF mode before the mode change. Therefore, it is possible to avoid performing the angle-of-view adjustment again after the mode change.

  As another display mode of the AF area on the LCD 311, for example, as shown in FIG. 15, the shape of the frame indicating the AF area may be different between the image AF area FR1 and the module AF area FR2. Alternatively, the frame indicating the image AF area FR1 may be displayed in red, and the frame indicating the module AF area FR2 may be displayed in blue.

  In FIG. 14 and FIG. 15, the module AF area FR2 is displayed on the image AF area FR1, and the area displayed so as to be recognized as the module AF area FR2 also functions as the image AF area FR1. That is, the area displayed as the module AF area FR2 in FIGS. 14 and 15 is also used for the AF operation using the image sensor 101.

  In the next step SP6 (FIG. 12), it is determined whether or not the finder mode has been switched. Specifically, when the contact position of the display changeover switch 85 is detected and the display changeover switch 85 is set to the OVF mode (the contact position is “optical”), the process proceeds to step SP11 to start from the EVF mode. The mode is changed (transitioned) to the OVF mode. Details will be described later.

  On the other hand, when the display changeover switch 85 is set to the EVF mode (the contact position is “monitor”), the process proceeds to step SP7.

  In step SP7, it is detected whether or not the shutter button 307 is half pressed. When the half-pressed state is not detected, the process proceeds to step SP6, and the process of step SP6 is executed again. If a half-pressed state is detected, the process proceeds to step SP8.

  In step SP8, the phase difference AF operation by the image sensor 101 is executed.

  In step SP9, it is detected whether or not the shutter button 307 is fully pressed. If the fully pressed state is not detected, the process proceeds to step SP6, and the process of step SP6 is executed again. When the fully pressed state is detected, the process proceeds to step SP10.

  In step SP10, shooting (exposure) is performed. Specifically, exposure by the image sensor 101 is started in a mirror-up state where subject light is incident on the image sensor 101. The image signal acquired by the image sensor 101 is subjected to predetermined image processing and recorded in the memory card 67 or the like.

  When the process of step SP10 ends, the process proceeds to step SP6, and the process of step SP6 is executed again.

  Next, a process when it is determined in step SP6 (FIG. 12) that the display changeover switch 85 is set to the OVF mode will be described.

  In this case, the process proceeds to step SP11, and the finder mode transitions (mode transition) to the OVF mode.

  Specifically, in step SP11, the mirror unit 103 is driven, and the mirror unit 103 enters a mirror-down state arranged in the optical path of the subject light.

  In the next step SP12, the shutter unit 40 is closed, and in step SP13, the image sensor 101 is stopped. In step SP14, the LCD 311 is turned off, and the process proceeds to step SP22 (FIG. 13).

  After the transition to step SP22, when there is no operation of the shutter button 307 and the transition of the finder mode is detected (step SP21), the transition is made to step SP2, and the mode transition is made from the OVF mode to the EVF mode (described later).

  As described above, in the EVF mode, live view display is performed on the LCD 311 based on the image signals sequentially generated by the image sensor 101, and the AF area Ef is displayed on the LCD 311. As the displayed AF area Ef, in addition to the image AF area FR1 used for the AF operation using the image sensor 101, the module AF area FR2 used for the phase difference AF operation by the AF module 107 is displayed.

  Next, a case will be described in which it is determined in step SP1 that the EVF mode is not selected (the OVF mode is selected) by operating the display changeover switch 85, and the process proceeds to step SP21 (FIG. 13).

  In this case, first, in step SP21, as in step SP6 described above, the contact position of the display changeover switch 85 is detected, and it is determined whether or not the finder mode has been switched. If the contact position is set to the OVF mode (the contact position is “optical”), it is determined that the finder mode has not been switched to step SP22, and the contact position is set to the EVF mode (contact point). If the position is “monitor”), the process proceeds to step SP2.

  In the next step SP22, as in step SP7 described above, it is detected whether or not the shutter button 307 is half pressed. When the half-pressed state is not detected, the process proceeds to step SP21, and the process of step SP21 is executed again. On the other hand, when the half-pressed state is detected, the process proceeds to step SP23.

  In step SP23, the phase difference AF operation by the AF module 107 is performed.

  In the next step SP24, it is detected whether or not the half-pressed state of the shutter button 307 is released. When the release of the half-pressed state is detected, the process proceeds to step SP21, and the process of step SP21 is executed again. On the other hand, if the release of the half-pressed state is not detected, the process proceeds to step SP25.

  In step SP25, as in step SP9 described above, it is detected whether or not the shutter button 307 is fully pressed. If the fully pressed state of the shutter button 307 is not detected, the process proceeds to step SP24, and the process of step SP24 is executed again. On the other hand, when the fully-pressed state of the shutter button 307 is detected, the process proceeds to step SP10 described above and photographing is performed.

  As described above, the imaging apparatus 1A combines and displays the module AF area FR2, in which the phase difference is detected by the distance measuring sensor of the AF module 107, with the preview image, so that AF control of the phase difference detection method is performed after the preview image is displayed. When performing the above, it becomes possible to avoid the angle-of-view adjustment again.

<2. Second Embodiment>
Next, a second embodiment of the present invention will be described. The imaging apparatus 1B according to the second embodiment functionally realizes an AF area defining unit 62D in the overall control unit 62, and shares the image AF area FR1 and the module AF area FR2 according to the setting by the user. FIG. 16 is a block diagram illustrating an electrical configuration of the imaging apparatus 1B. FIG. 17 is a diagram illustrating a display example of the AF area on the LCD 311.

  Note that the imaging device 1B according to the second embodiment has substantially the same configuration and function (see FIGS. 1 to 4 and 16) as the imaging device 1A according to the first embodiment. Are denoted by the same reference numerals and description thereof is omitted.

  As illustrated in FIG. 16, the overall control unit 62 of the imaging apparatus 1B functionally displays the display control unit 62A, the phase difference AF control unit 62B, the contrast AF control unit 62C, and the AF area defining unit 62D by executing the program. Realize.

  The AF area defining unit 62D performs control so as to acquire focus information used for the phase difference AF operation or the contrast AF operation by the image sensor 101 in the module AF area FR2 used for the phase difference AF operation by the AF module 107. That is, the AF area defining unit 62D unifies the AF area by defining the image AF area FR1 in the area (also referred to as “corresponding area”) indicated by the module AF area FR2 in the image sensor 101.

  When the module AF area FR2 and the image AF area FR1 are shared by the AF area defining unit 62D as described above, the phase difference AF operation by the AF module 107 is displayed on the LCD 311 as shown in FIG. The module AF area FR2 that can be used for the display is displayed (step SP5 in FIG. 12).

  Also, whether or not to share the AF area can be determined by a menu operation on the menu screen displayed on the LCD 311.

  As described above, the imaging apparatus 1B further includes the AF area defining unit 62D that defines the image AF area FR1 in the corresponding area indicated by the module AF area FR2 in the imaging element 101 in addition to the configuration of the imaging apparatus 1A. According to this, since the image AF area FR1 in the EVF mode and the module AF area FR2 in the OVF mode can be shared, the user can perform framing without worrying about the AF area shift between the finder modes. It becomes possible to do.

<3. Third Embodiment>
Next, a third embodiment of the present invention will be described. In the imaging apparatus 1A according to the first embodiment, the image AF area FR1 and the module AF area FR2 are simultaneously displayed on the LCD 311 during live view display (step SP5 in FIG. 12). In the imaging apparatus 1C, the display mode of the AF area on the LCD 311 is changed according to the user setting.

  Note that the imaging apparatus 1C according to the third embodiment has the same configuration and functions as the imaging apparatus 1A according to the first embodiment, except that the display control unit 62A has the AF area display mode change function ( 1 to 5).

  As described above, the display control unit 62A of the imaging device 1C performs the live view in response to a user operation (specifically, a menu operation or an operation using an operation member such as a button provided on the imaging device 1C). A function of changing the display method of the AF area displayed on the LCD 311 at the time of display (AF area display mode changing function) is provided. FIG. 18 is a diagram showing a method for displaying the AF area on the LCD 311.

  Specifically, as illustrated in FIG. 18, in the imaging apparatus 1 </ b> C, the user sets the display mode HM <b> 1 that simultaneously displays the image AF area FR <b> 1 and the module AF area FR <b> 2 on the LCD 311 and hides the image AF area FR <b> 1. The display mode HM2 for displaying the module AF area FR2 on the LCD 311 can alternatively be validated.

  As described above, according to the imaging apparatus 1C having the display change function, the user can change the display method of the AF area in live view display according to his / her preference.

1 is a diagram illustrating an external configuration of an imaging apparatus according to a first embodiment of the present invention. 1 is a diagram illustrating an external configuration of an imaging apparatus according to a first embodiment of the present invention. It is a longitudinal cross-sectional view of an imaging device. It is a longitudinal cross-sectional view of an imaging device. It is a block diagram which shows the electrical structure of an imaging device. It is a figure for demonstrating the structure of an image pick-up element. It is a figure for demonstrating the structure of an image pick-up element. It is a figure for demonstrating the principle of phase difference AF using an AF line. It is a figure which shows the relationship between the light beam which injects from the exit pupil of an imaging lens, and AF pixel of an image pick-up element. It is a figure which shows the pixel output of AF line. It is a figure which shows the shift amount and defocus amount of pixel output. It is a flowchart of imaging operation of an imaging device. It is a flowchart of imaging operation of an imaging device. It is a figure which shows the example of a display of the AF area on LCD. It is a figure which shows the example of a display of the AF area on LCD. It is a block diagram which shows the electrical structure of the imaging device which concerns on 2nd Embodiment. It is a figure which shows the example of a display of the AF area on LCD. It is a figure which shows the display method of the AF area on LCD.

Explanation of symbols

1A, 1B, 1C Imaging device 101 Imaging element 103 Mirror part 107 Phase difference AF module 311 LCD
62 Overall Control Unit 62A Display Control Unit 62B Phase Difference AF Control Unit 62C Phase Difference AF Control Unit 62D Area Setting Unit 72A Mirror Drive Control Unit FR1 Image AF Area FR2 Module AF Area

Claims (4)

An image sensor that receives subject light and generates an image signal related to the subject image;
A display unit;
A mirror unit disposed on the optical path of the subject light and changing the optical path of the subject light;
A phase difference detection unit that receives the subject light whose optical path has been changed by the mirror unit with a distance measuring sensor and generates a phase difference detection signal;
First focusing means for performing first focusing control based on the phase difference detection signal in the first area where the phase difference is detected by the distance measuring sensor;
Mirror control means for retracting the mirror unit from the optical path;
Display control means for displaying a preview image before the main photographing on the display unit on the basis of image signals sequentially generated by the imaging element in a state in which the mirror unit is retracted from the optical path;
Second focusing means for performing second focusing control based on an output signal acquired from the second area of the image sensor;
An optical viewfinder mode that includes area defining means for defining the second area at a position corresponding to the first area in the imaging device, and displays the subject image on the optical viewfinder in a state where the mirror unit is retracted from the optical path. And an imaging device capable of switching between an electronic finder mode for displaying the subject image on the display unit in a state where the mirror unit is not retracted from the optical path,
The display control means includes the second focus when the mirror area is retracted from the optical path and the first area to be subject to the first focus control when the mirror is not retracted from the optical path. Combining the second area to be controlled, combining and displaying the preview image in a state in which the mirror unit is retracted from the optical path,
An imaging apparatus in which the second focusing control is performed by the second focusing means when the preview image is displayed. The imaging apparatus according to claim 1, wherein the output signal is the image signal generated by the imaging element. The imaging element has a light receiving element for phase difference detection on the imaging surface,
The imaging apparatus according to claim 1, wherein the output signal is a signal output from the light receiving element. The display control means alternatively selects a first display mode for displaying the first area on the display unit and a second display mode for displaying the first area and the second area on the display unit. The imaging apparatus according to claim 1, further comprising a display mode changing unit that is activated.

Images